Request to add a DeepSeek Chat model to turn off the Think Chain switch

[fsea]

Self Checks

• I have searched for existing issues search for existing issues, including closed ones.
• I confirm that I am using English to submit this report (我已阅读并同意 Language Policy).
• [FOR CHINESE USERS] 请务必使用英文提交 Issue，否则会被关闭。谢谢！:）
• Please do not modify this template :) and fill in all the required fields.

1. Is this request related to a challenge you're experiencing? Tell me about your story.

Sometimes you don't need to output a chain of thoughts, so it's recommended to add a switch

2. Additional context or comments

No response

3. Can you help us with this feature?

• I am interested in contributing to this feature.

[crazywoola]

Will do later :) The short term thing is we need to add deepseek for all kinds of providers. See the milestone here https://github.com/langgenius/dify/milestone/12

[crazywoola]

Partly #13263 but not for all the providers.

[zxfishhack]

Is it a good idea to add the Enable CoT Trim option in OpenAI-API-compatible and configure the start and end markers of CoT (such as in the deepseek-r1 series)?
Then remove the Think Chain in the OpenAI-API-compatible implementation.